1. Field of the Invention
The present invention relates to a swash plate type compressor for compressing a refrigerant gas by rotations of a swash plate, and more particularly relates to an improvement to a sliding surface of the swash plate to provide it with excellent seizure resistance with shoes although it is exposed to extremely severe working conditions during the high load operation of the compressor.
2. Description of the Prior Art
Conventionally, a swash plate type compressor is used in systems such as an air conditioning system of an automobile. According to a known swash plate type compressor, the transmission of motive power is carried out as a swash plate rotates and shoes are slidably rolled between the swash plate and a piston to reciprocate the piston, thereby suctioning, compressing and discharging the gas. The swash plate is usually composed of aluminum or aluminum alloy and the shoes are composed of iron or ceramics such as alumina in consideration of the weight reduction of the parts. The swash plate has slidable contacts with the shoes when it rotates.
In the conventional swash plate type compressor, the following problems are likely to occur.
1). Under such unfavorable circumstance as when the refrigerant leaks outside from the swash plate type compressor, the absolute amount of oil contained in the refrigerant gas is decreased. If the swash plate type compressor is operated under this state, lubrication at the sliding surface of the swash plate is decreased and, in an extreme case, seizure of the shoe at the sliding surface of the swash plate occurs due to the generation of high temperature friction heat.
2). Also, in the case where the compression of a liquid refrigerant takes place, the lubrication at the sliding surface of the swash plate is decreased. As a result, seizure of the shoe at the sliding surface of the swash plate may possibly occur.